On a test, Shoshana got 65% or 23.4 of the items correct? How many items were on the test?
2 answers:
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Answer:
50m/s
Step-by-step explanation:
We assum the direction the baseball is travelling to the bat is the positive direction at 20 m/s and is hit in the opposite at a faster speed. The change in velocity is the final velocity minus the initial velocity:
The change in velocity is 50m/s
Answer:
a)
And then the probability that Fred will not score between 47 and 77 is
1-0.968 = 0.0321
b)
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Part a
Let X the random variable that represent the scores of a population, and for this case we know the distribution for X is given by:
Where and
We are interested on this probability on the probability that Fred will not score between 47 and 77. So we can begin finding this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability on this way:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.
And then the probability that Fred will not score between 47 and 77 is
1-0.968 = 0.0321
Part b
And we can find this probability on this way:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.